P0021: “A Camshaft Position (Bank 2) – Timing Over-Advanced or System Performance.”

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🔍 Code Meaning

P0021 indicates that the intake camshaft on Bank 2 (Camshaft “A”) is more advanced than the ECM/PCM expects.
This usually points to a Variable Valve Timing (VVT) or Oil Control Valve (OCV) issue.

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⚙️ Possible Causes

1. Dirty or low engine oil (most common)

2. Faulty VVT solenoid / Oil Control Valve (OCV) on Bank 2

3. Timing chain stretched or incorrectly aligned

4. Camshaft phaser stuck in advanced position

5. Oil passages to the VVT system clogged

6. Faulty camshaft position sensor (Bank 2, Sensor A)

7. ECM (rarely) malfunction

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🧰 Diagnosis Procedure

1. Check Engine Oil:

Verify correct oil level and condition.

If oil is dirty or thick, change oil & filter first.

2. Inspect Electrical Connections:

Check the VVT solenoid connector and wiring for damage, corrosion, or loose fit.

Measure voltage and ground at the solenoid.

3. Test the VVT Solenoid (OCV):

Apply 12V and ground manually to see if the solenoid clicks.

If no click or weak movement → replace the solenoid.

4. Inspect Timing Components:

Use scan tool to view camshaft angle vs. desired angle.

If out of spec or fluctuating, remove timing cover and inspect timing chain, guides, tensioner.

5. Check Cam Phaser:

If phaser is stuck or oil passages clogged, it may stay in “advanced” position.

Clean or replace as needed.

6. Camshaft & Crankshaft Sensor Check:

Ensure both sensors are working correctly and giving consistent signals.

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💡 Professional Tips

Always clear the code and perform a road test after each repair step.

Use OEM or high-quality oil filters; poor filters can reduce oil pressure to the VVT.

On many Nissan, Infiniti, Ford, and Toyota engines, dirty oil or clogged OCV is the #1 cause.

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🧾 Common Repairs

Repair Action Typical Outcome

Change engine oil & filter Often fixes issue
Replace Bank 2 VVT solenoid Very common fix
Clean oil passages Resolves sticking actuator
Replace timing chain or phaser Fixes mechanical cause
Replace cam sensor If signal faulty

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